Flush head locked-in fastening device



y 951 J. ROSAN 2,550,867

FLUSH HEAD LOCKED-IN FASTENING DEVICE Filed Aug. 12, 1948 2 Sheets-Sheet1 Josenq Roan/v, INVENTOR.

HTTOQA/EV y 1951 J. ROSAN 2,550,867

FLUSH HEAD LOCKED-IN FASTENING DEVICE Filed Aug. 12, 1948 2 Sheets-Sheet2 JosEpfl 20.5w,

I N V EN TOR.

Patented May 1, 1951 FLUSHTHEADLGCKED-IN ASTENING,

, e enh Be a xl oals and, Qalif- Application Augnst--l2, isasgsriariiaaasas .1 l The present invention deals generallyawith fasteningdevices in the naturenof boltsand :nuts, particularly those designed tobe installed and locked in a flush-headposition.

Flush head bolts as known todayv are commonly formed with a socketedhead, square or hex agonal, adapted to receive a .iwrench byswhichtorque can be applied theretoto drive them into positionin the work.These sockets, howevendf 'made large enough to receive a-wren-chlbywhich the desired torque .can beaexerted, ,have the reflfect ofweakening the bolt, andathe bolt some-.- times fails inhservice becausev.of .:this.,condi.tion. Moreover, no completely satisfactory \method oflocking these prior .art bolts securely iniplace from the head endthereof hasibeen-found.

A primary object of the invention therefore to provide a, flushheadbolt-of inereasedistrength and durability, haying improvedmeans bywhich it may be driveniinto;theiwork,land havingralso effectiveprovision for securely locking its-against removal. a

A further object islto providesuchabolt-and locking meanstherefor,capable of.z;being-;readil removed from the work by a simplemaninulaation, without damagecto the work. i

A still'further, object ofthe invention is to -prpvidea nut havingock-mend rem valcharacterr istics of the same kgeneral-nature as thebolt of the invention. r

The ,invention, as well, ,as ;yar ious additional,

jects thereof, and i swarious .feature ian a vantages, will behesunderstood-.-f om e ensuing description vof a present preferr dzillustrativeembodiment thereof, reference forthis purpose beingdirected to. the, accompanyin drawings, wherein;

Fi re :1 isan exp d .zvi w .showing ia bol aac or c w t the i n ion inside ele tion and a ck nstri th efo n ran vers section immediately abovethe head of thebolt;

Figure 2 is a view showing thB' b01t of ;the,inn iq s alled, t e o t b iagain sh wn :i side elevation, and the locking ring in medial sec tion;

Figure ,3 is a; fragmentary plan view of ,the bolt hea an lo n r e effiiu ezi F u 1 1 a v r w zs m a to Fi ure; 2 showin the bolt being driveninto position by theinstalling wrench;

Figure 5 is a similar view, but showing the locking ring being driveninto position by the wrench us'edin inverted position;

Figure 6 isa-similar view but showing the locking ring having beendriven downwar dly bythe was, Isl-e32;

, ,2 same installing tool itolpermit removal .of :the bolt;

Figure 7 shows thetprocedure of removing'ithe bolt and locking ring froltheiwork'; land Figure 8. is :a view,l..partially in three=quartersection, showing the application oftthe inventiontoanutr 1 V V Referring-now to the drawings, numeral slat! designates ,generally .thecylindrical shank -ofaa machinei-screwaor bolt, :having a, screwthreadedinner or forward end. section I .andthavingl-at the outer or uppervendethereof an enlarged rounded head tors-body 12. I This :head I52has-sat theltop a band loft longitudinally gor axially .directed lockingformations-preferably :in the-form of serrations .I3 ofsubstantiallyetniangularlouty line, .such as illustrated bestin Figure.3; 1n the present preferred embodiment, these serrations I 3. occupyonly-,;substantia11y.;the upper aof the head i2 .andin any event theywilktermmate substantially short tor the loweriendlof theheaid. for apurpose resently ,to, appear. Below-512116 band of serrations J:.3,v.the.head Shasa cylindrical section IA of reduced diameter,,thencdiametrtqf.

said .section 14 being; no-greaterethanath 211 3 fl ameteraoffltheserrations ii. If; d sire thechead L2 m y beregardedlas, underrcut belowthe senrations 13; ,to pr s/idea :resiuaed neckiaportion 1,4 of, no greaer diameter than the root diameter of the serrations. sBreferabl-yeandasanuadded feat re .h vina an imp rtan function 5.15.0 a pear pres ntly.lth head A2 has atthebofloman-enar ed annula name .15; preie iablybfappraisma ly th same. diameter .vas, a 1 littl lar r than, the peakibcreshdimeter or the..;serrationsil Ope bl V 0911i motion with the boltasathus d scr be is a clocking-ring J5 ,chara tar istics similar to t elocking arms disclosed; nimy rio Pa ent .-,;.L I;umb A lLB L8, :issued,May 1st This-.ilo k n no L6 eha internalule gir udin lly 9 .a iall ldizecteii loc ing 'ienmations ad eat me eo me h the .l ekingiormame nitheheadbtthe bolt In the br ferredv se of ,thase ra m t3 the. bQlt-theseint111L811 loc formati ns in the, urse s th s r ations,

holtheadl the1:s r t pn v lare m lie indifla da 1 ha es be is a s .p gvde with exter a eration prei ra lvof sub tantially t an ul Q m tian seFi e. 73 andi he artari to a point a little below the middle thereof,where they terminate to form the ring with a reduced pilot portion 20for a purpose to appear hereinafter. As will be seen from an inspectionof Figure 1, the pilot formation 20 is actually, preferably, of slightlyless diameter than the root diameter of the serration I9. Theseserrations 19 are designed to constitute broaching elements adapted tocut their way into the walls of a counterbore into which the head of thebolt is installed, as will presently be described.

In Figures 2, 4 et seq., the bolt has been shown as threaded into ascrewthreaded bore 24 in a body 25, and as securing to said body 25 amember 26 which has been bored at 21 to pass the bolt, and which hasalso been counterbored at 28 on a diameter sufiicient to accept the bolthead and locking ring, and to a depth sufiicient to receive the bolthead in a flush position. The member 26 will be understood to be amember of somewhat softer characteristics than that of the looking ring,to permit broaching by external serrations [9 of the latter. Inparticular, the counterbore 28 is substantially the same diameter as theroot diameter of the external serrations 19 of the locking ring.

Figure 4 illustrates the procedure and implement employed to install thebolt, the numeral 30 indicating an installing wrench having a reducedthin-walled end section 3| defining a socket formed with internalserrations 32 adapted to receive and mesh with the serrations I3 on thebolt head. It will readily be understood how this wrench is engaged withthe serrations l3, and how it is employed within the counterbore 28 toturn the bolt down until its shoulder 33 engages the upwardly facingshoulder 34 formed by the counterbore 28.

Figure shows the locking ring l5 after being driven into position byusing the other end portion 35 of the wrench tool 30 as a driving tool.This end portion 35 of the tool 30 has an annular driving face 33adapted to engage the upper face of the locking ring l6, and it will beunderstood that the procedure is first to drop the pilot portion 20 intothe annular space between the serrated portion l3 of the bolt and thewall of the counterbore, the chamfer at l8 facilitating the entry. Theunder-sides of the serrations It will at first engage theupper face ofthe member 26 around the outside of the counterbore. The tool- 30 isthen hammered to drive the ring downwardly to the position illustratedin Figures 2 and 5, it being appreciated that the serrations l9 functionas broaching elements to cut their way into the side walls of thecounterbore 28. Thus, the locking ring is engaged in intimaterelationship with the material of the member 26, in such a way that itwill not loosen or become displaced in service. It will further beappreciated that the bolt is locked securely against turning by thelocking ring, as well as being locked against axial movement by itsscrew threads H. The bolt is thus completely immobilized against thesligh*- est movement with reference to the bodies 25 and 26, and eventhe slightest degree of play, such as in time will operate to loosenmany types of fastening devices, is positively prevented.

One of the principal features of novelty of the present device is theprovision whereby the bolt may be readily removed after having beenpermanently locked in place by the locking ring I6. Figures 6 and 7 showhow this operation is performed, Figure 6 showing the wrench tool 30again used with its thin-walled internally ser- 4 rated end portionengaged with the bolt. The operation is performed by accurately locatingthe wrench on the bolt head, with its serrated socket in alinement withthe serrations [3 of the bolt head. By then driving it downwardly, usingany convenient striking tool, the locking ring i6 is driven downwardlyfrom its original locking position of Figure 5 to such a position asillustrated in Figure 7, where the serrated portion l3 of the bolt isclear of the locking ring. The wrench tool 30 is then simply turned tounscrew the bolt from the work. The flange 15, when provided, operatesin this procedure to engage the locking ring l6 and lift it out of thecounterbore, as illustrated in Figure 7. It will of course be evidentthat in the event the flange I5 is omitted, the boltwill be completelyunscrewed from the work by the operation described, but that the lockingring would be left in the position of Figure 6. It could then be priedout of the socket by a very simple operation. It is, however, of verygreat advantage to employ the fiange l5 on the head of the bolt for thepurpose of engaging the looking ring and lifting it out of the socket atthe same time that the bolt is removed from the work.

Figure 8 shows the application of the invention to a nut. In thisfigure, numeral 49 designates the threaded shank of a bolt, extending upthrough members 4| and 42 from below. Numeral 43 designates the nut ofthe invention, and it will be seen that the body of this nut has thesame contour and features as the head or enlarged body [2 of the bolt ofFigure 1. Thus, the nut has upper serrated section 44, reduced orunder-cut cylindrical portion 45 below serrated portion 44, and enlargedring-removing flange 46 at the'bottomj Used with this nut is a lockingring 50 identical with the ring 16 previously described, and which willbe seen to have external broaching serrations 5|, internal serrations 52adapted to mesh with serrations 44 on the nut. reduced pilot portion 53,and, of course, internally threaded bore 54 adapted for engagement withthe threaded shank of the bolt to. The procedure of installing the nutis in all respect similar to that already described in connection withthe bolt, and a repetition will not be required.

'A noteworthy feature of the invention is that the bolt, or nut, as thecase may be, may always be reinstalled, using the same locking ring, andthe reins.allation will leave the bolt or nut as secure as it was in thefirst instance. This is owing to the fact that with even the most carein manufacture, the serrations on the locking ring will not be identicalin size, shape, and spacing, nor will the ring be perfectly round. onreinstallation, the ring almost never goes back in exactly the sameposition as it was in originally, and because of the minor distortionsmentioned, there is accordingly adequate tightness of fit onreinstallation.

Certain present illustrative forms of the invention have now beendescribed, but it will be understood that these are for illustrativepurposes only, and that various changes in design, structure andarrangement may be made without departing from the spirit and scope ofthe invention.

I claim:

1. A fastening element embodying a screwthreaded cylindrical shank, anenlarged circular head integrally formed at one end thereof, a

band of longitudinally directed locking serra-. tions formedaround anouter extent of said' head, head also having, adjacent said band ofserrations, a reduced peripheral extent of no greaterdiameter than theroot diameter of the.

serrated portion of said head, a separate locking ring having externallongitudinally directed broaching serrations and longitudinally directedinternal serrations adapted to mesh with said serrations on said head,said reduced inner extent of said head being of a width dimension,measured axially of said head, at least as great as the length of theinternal serrations on the locking ring, whereby the intermeshinglocking engagement between the head serrations and the ring serrationscan be broken by axial movement of the locking ring to a positionopposite said reduced peripheral extent of said head, thereby permittingrelative rotation of said head within said ring, and a radiallyprojecting portion on said head between said reduced extent and saidshank adapted to engage under said locking ring to lift the same fromthe work when the head and shank are unscrewed therefrom.

2. A fastening element embodying a screwthreaded cylindrical shank, anenlarged circular head integrally formed at one end thereof, a band oflongitudinally directed locking serrations formed around an outer extentof said head, said head also having, adjacent said band of serrations, areduced peripheral extent of no greater diameter than the root diameterof the serrated portion of said head, a separate locking ring havingexternal longitudinally directed broaching serrations and longitudinallydirected internal serrations adapted to mesh with said serrations onsaid head, said reduced inner extent of said head being of a widthdimension, measured axially of said head, at least as great as thelength of the internal serrations on the the locking ring, whereby theintermeshing looking engagement between the head serrations and the ringserrations can be broken by axial movement of the locking ring to aposition opposite said reduced peripheral extent of said head, therebypermitting relative rotation of said head within said ring, and aradially projecting flange of a diameter sufiicient to underlie aportion of said locking ring formed on said head between said reducedextent of said body and said shank.

3. A fastening element embodying a body of essentially circular outline,a band of longitudinally directed locking serrations formed around anouter extent thereof, said body having immediately adjacent and inwardof said serrations a reduced peripheral extent of no greater diameterthan the root diameter of the serrated portion of said head, a separatelocking ring having external longitudinally directed broachingserrations and longitudinally directed internal serrations adapted tomesh with said serrations on said body, said reduced extent of said bodybeing of a width dimension, measured axially of said head, at least asgreat as the length of the internal serrations on the locking ring, anda radially projecting flange of a diameter sufiicient to underlie aportion of said locking ring formed on said body on the opposite side ofsaid reduced extent of said body from said serrated band.

4. A fastening element embodying a screwthreaded cylindrical shank, anenlarged integral head at one end thereof, said head having an outerextent formed with longitudinally directed locking formations, and aperipheral undercut extent adjacent and inward of said lockingformations, a separate locking ring having external longitudinallydirected broaching serrations, and internal longitudinally directedlocking formations adapted to'mate with said locking formations on saidhead to lock said head and ring against relative rotation, said undercutextent of said head being of a dimension, measured axially of said head,at least as great as the length of the internal serrations on thelocking ring, and

said locking ring being movable axially along said head to a positionbeyond said locking formations on said head and opposite said undercutextent of said head, where said head is free to turn within said ring,and a radially projecting portion on said head between said undercutextent and shank adapted to underlie at least a portion of said lockingring to lift the same from the work when the head and shank areunscrewed therefrom.

5. A fastening element embodying a body of essentially circular outline,longitudinally directed locking formations formed around an outer extentof said body, and a peripheral undercut extent adjacent and inward ofsaid locking formations, a separate locking ring having externallongitudinally directed broaching serrations, and internallongitudinally directed looking formations adapted to mate with saidlocking formations on said body, said undercut extent of said body beingof a dimension, measured axially of said head, at least as great as theinternal serrations on the locking ring, said locking ring being movableaxially along said body to a position beyond said locking formations onsaid body and opposite said undercut extent of said body, where saidbody is free to turn within said ring, and a radially projecting portionon said head on the opposite side of said undercut extent from saidlocking formations, said radially projecting portion underlying saidlocking ring to engage and lift the same from the work when the head andshank are unscrewed therefrom.

' JOSEPH ROSAN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

